The genetically amenable yeast, Saccharomyces cerevisiae, will be used as the model system in the study of germination. Germination is the process of exiting a stage of quiescence (ie. a yeast spore) to that of vegetative growth. This process is important for the life cycle of yeast as well as mandatory for infection by spores of opportunistic yeast pathogens. This study is likely to advance our knowledge of Ras and protein kinase A signaling and hopefully can be extended to understand physiological events in higher eukaryotic systems. A genetic screen will be used to initiate this study. One screen is designed to isolate temperature sensitive germination mutants. In addition, DNA microarray analysis will be performed to identify targets of the Ras/PKA pathway of S. cerevisiae as well as to investigate the possibility of a Ras-independent pathway in germination. Lastly, the role of the glucose sensitive G- protein coupled receptor system in germination will be investigated. Through these experiments, I hope to gain insights into the molecular events that regulate this important stage of the yeast life cycle.